1. Field of the Invention
The inventions described below relate to the field of medicine and more specifically, to providing body cavity illumination for use in medical, dental and veterinary procedures.
2. Background of the Invention
Existing technology for illumination during surgical/medical procedures is often limited to overhead illumination. This illumination comes from either overhead lighting or head mounted fiber optic systems. Traditional overhead lighting systems face numerous limitations. Direct exposure of the field from the overhead source is required. Changes in patient or surgeon positioning requires repositioning of the light source. Frequent adjustments provide an inconvenience for the surgeon and disrupt the surgical flow. For deeper cavities, overhead systems provide poor quality illumination. Positioning of the surgeon, or the instruments may shield the overhead lighting and prevent illumination from reaching the field of the procedure.
Head mounted fiber optic systems are used frequently for more limited surgical exposures, however, these devices also have numerous drawbacks. First, the surgeon is tethered by the light cord attached to the headset, limiting mobility in the operating room. Second, the devices are associated with head and neck fatigue with frequent or more prolonged use. Third, the devices require the surgeon to maintain a steady head and neck position to provide a constant and steady illumination of the field. Fourth, the use of remote light sources and fiber bundles introduces tremendous inefficiencies into the system. A six-foot fiber optic cable may lose 65% of the incoming light from a light source. The headlamp optical components may lose another 60% of the light from the fiber optic cable. In addition, surgeons using head mounted systems frequently complain of the heat generated by such systems.
In addition, both headlamp and overhead systems provide inadequate illumination when used with less invasive surgical procedures with a limited incision to access a deeper or broader surgical cavity. For these cases, both overhead and headlamp systems only illuminate a fraction of the volume of the surgical space.
The introduction of minimally invasive surgical techniques, has raised the demand for delivery of high intensity light through minimal surgical incisions into deep surgical fields. To address this demand, light delivery devices have been developed for delivery of light from remote, high intensity light sources to the surgical field. These devices generally consist of bundles of optical fibers that are integrated with or directly adhere to surgical retractors to illuminate the field and are connected via fiber optic cable to a high intensity light source. While these devices provide a way to illuminate the surgical field, they provide highly inefficient illumination. The small bundle diameter is susceptible to being completely blocked by any surgical debris or splatter such as blood or tissue, thereby requiring constant cleaning to maintain illumination. In addition, due to the limited divergence angle and highly Gaussian intensity profile, these devices only provide a small spot of light that requires constant repositioning to view the entire surgical area. In addition, these fiber optic light pipes are very expensive to manufacture, requiring significant amounts of expensive human labor.
Waveguide illuminators are known in the art and typically allow light to exit the illuminator by using optical structures molded into the surface of the waveguide itself. Light injected into such waveguides is typically contained in the waveguide through total internal reflection. When the light strikes the optical structures, the reflection angle is interrupted such that the light now refracts out of the waveguide. Such systems may be useful for illumination of deep tissues, but often require the use of expensive, specialized tooling or manufacturing processes. Moreover, these waveguides are rigid and must be designed to fit particular instruments so different waveguides must be available to accommodate the variety of surgical instruments used in a given surgical procedure.
Still other applications may involve woven fiber optic strands or fiber optic strands cut at various lengths to generate diffuse lighting. Light escapes the fiber either through a nick in the surface of the fiber or because a material has been applied to the surface of the fiber that disrupts total internal reflection, or the light merely escapes out of the cut ends of the fiber. This type of diffuse illumination is typically not suitable for illumination of deep tissues because it provides an insufficient level of illumination for tissues of interest and often shines light back into the surgeon's eyes, making viewing of the tissues difficult. Such systems are also expensive to manufacture.